The off grid season has started

Haven't had the heating back on. Could have done with fire in sittting room Wednesday night, as much to dry off. Looking forward to export season now, propping up the grid and paying for winter.

I'm charging based on a low forecast or if the battery is not high enough to see through to morning it charges to a min amount. Personally I wouldn't be dumping to the grid at the current rate. If we had the likes of Octopus agile here where you could get a higher export at peak times I'd consider it.

I think everyone has a different goal with this. Mine is minimum grid use (and cost).

Sounds like you're trying to maximise export, while not buying anything except EV-rate (2am-4am) from the grid?

You could possibly achieve this a bit easier, without actually cycling the battery.

Here's what my automatons are doing from now through summer, with a Solis Hybrid, large array, large battery, and export (back flow) capped to stay under the 6kw. Where EV-rate import is 7 cents, and export is 25 cents.

I expect the below alone could be worth a couple of euro a day on top of the normal export, come the good days in May/June/July. And it's pretty simple automations so no daily effort. Agreed, the summer can cover the winter usage and standing charge for big setups, and leave you up over the course of a year.

• During the EV window, charge the battery if necessary, to bring to an SOC proportional to your forecast. I vary from 60% to 100% depending on forecast: 60% for a super day, 95% for a bad summers day (i.e. 25kwh or so).
• Set the backflow limit on the inverter, so you dont exceed the grid limits (do this once ever)
• Set the inverter to Feed In Priority (FIP) mode each morning right after the EV window (i.e. before sunrise)
• So now, all generation from the start of the day will be consumed by the house or exported (battery wont charge). Also, any time you consume more than generation it'll be taken from the battery
• The battery SOC may drop a little during the first couple of hours of generation, thats fine.
• When you get towards peak (midday) generation (more than you are are allowed export), the inverter will dump the remainder into the battery automatically. e.g. it'll send 6kw out to the grid, 100w to house base load, and the rest will go into the battery.
• So, your battery is now charging with the truly free electricity (i.e. you are exporting the max allowed, running the house, and also charging the battery with what would not even be generated otherwise)
• Over time as you see how your own system behaves, you can make better guesses as to what to charge the battery to in step one, based on your daily forecast. I would aim that you map it so that the battery will probably hit 95% during the day, so that there is some space left if you have better production than expected.
• Depending on your forecasts/night usage/battery capacity, you may have enough left in the battery to not even need an EV-rate charge (or can dump from the battery in the evening and recharge at EV-rate - I don't do this. But its only one discharge for the day, so wont be an issue)

And as for the Eddi:

When on Smart Tariffs with good FIT/low EV rates, the standard way of using an Eddi doesn't really add up: its better to boost it at EV-rate than waste potential FIT during the day.

It does have good use though if you have more generation that can be exported: instead of setting the standard export margin at 0W (or 150W or whatever), set it to near your grid export limit. So, then the eddi wont kick in until you're almost maxing out the grid export limit. Again, it'll take the the power you wouldn't have been generating otherwise, same as was done for the battery.

Note: This is the basic idea. You'd need a bunch of safeguards to disable the above during a day where production/usage didn't go as expected, so you'll always last until EV-Rate. For instance, I have hourly/by minute forecasts: so forecast what generation is remaining at each point during the day to make sure there is enough to get to 2 AM.

4 of the last 7 days I think this approach would be very beneficial indeed. I’m going to try it. But I fear my 10kWh battery is too small to give me this freedom; but I’ll let ya know how it goes.

Good sun today, managed to fully top up my 8kwh of off grid batteries. That should cover the cooking, washing machine and tv for the week.

Great. And it's only going to get better for the next few weeks. I got few kwh extra out of today too using this system. Some into the Immersion and some into the battery.

As for disabling it, yea, a little after the peak is pretty good. Or, here's what I'm doing:

• Have a good solar forecast by hour/minute, where you always know how much generation is left for the day. Represent this as a (template) sensor that updates (every minute) with how many wh of generation is left for the day, per your forecast.
• Have another template sensor that updates with roughly how many wh you need from now until the EV window tomorrow morning. Look back on previous days to know how much you use at various times of the day to formulate this sensor (my sensor updates each minute)
• With both of these (and battery SOC) you now can track excess capacity you have left for the day, at every minute during the day (template sensor). i.e. (RemainingForecastWh + BatteryUsableWh) - NeededUntilEvWindowWh = ExcessWh
• When ExcessWh goes negative (or low), then its time to disable

Getting a pretty accurate ExcessWh sensor takes a little work to set up, but you may find a lot other uses for it, where it can really simplify other tricky automations. For example, during winter time you can use it to automatically dump some power into electric rads without risking running out before Ev Window. e.g. If ExcessWh > 3000 Then turn on heater until ExcessWh < 2000.

RE your comment on Eddi "So your essentially using the eddi as an export limiting device rather than setting that in the inverter."

Not quite: the inverter has the export limit set, so it doesn't abuse the grid. The Eddi has its margin set a little below the inverter export limit. So, when you approach the inverter export limit, the eddi will kick in.

I’ve taken a slightly different approach today.

I have left the excess power on charge; and will let the system charge to 90% at which point I’ll change the mode to feed the excess to grid. It’s likely this will happen before we reach the peak time so I shouldn’t loose any excess. Edit: now that I’ve thought about it I won’t loose any; I would only loose some of the battery got to 100%.

Then if there is enough excess above my 6kw inverter to charge the battery to 100% at some point in the day; I change the mode of the battery to dump it to the grid down to 90% again and repeat.

I prefer to know I’ll have the battery at 90% at least; your solution works too; but I didn’t have time to get into it in that much detail yesterday evening.

will let ya know how it goes.